One in every four new vehicles sold in America today is an SUV. Indeed, SUVs are the most popular vehicles on the road -- and the most profitable. Some manufacturers make up to $15,000 in profits on every SUV that rolls off the assembly line. The sport utility vehicle is one of Detroit's greatest success stories, credited with saving the U.S. auto industry.

But the SUV has a serious safety problem: its tendency to roll over. There will be an estimated 70,000 SUV rollovers in 2002, in which some 2000 people will die.

In "Rollover: The Hidden History of the SUV," FRONTLINE examines whether America's most popular vehicle may also be one of its most dangerous, and investigates why automakers and government regulators failed to do more to protect and inform American consumers.

The dangers of SUVs were spotlighted in the fall of 2000, when the sensational Ford-Firestone scandal prompted Congress to launch a series of hearings focusing on deaths and injuries related to faulty Firestone tires mounted on Ford Explorers. But, during the same 10-year period in which Ford-Firestone rollover crashes caused some 300 deaths, more than 12,000 people -- 40 times as many -- died in SUV rollovers unrelated to tire failure.

"The Firestone deaths are just the tip of the iceberg when it comes to problems with sport utility vehicles," says Keith Bradsher, former Detroit bureau chief for The New York Times. "We are ignoring the elephant in the tent, which is the much broader problem created by sport utility vehicles, and not just the Explorer."

How did a vehicle with such a serious safety problem become so popular? How much did automakers know about the SUV's rollover record? And why didn't the federal government do more to protect American drivers? These are some of the questions FRONTLINE explores in this report. Through interviews with federal auto-safety regulators, auto industry figures, policymakers and observers, FRONTLINE investigates the hidden story behind the staggering number of SUV rollover accidents and examines the regulatory free ride that the SUV has enjoyed. The documentary also explores how auto industry opposition and a political commitment to deregulation kept regulators from issuing rollover rules and, at the same time, protected the SUV from fuel-efficiency standards.

"Rollover" traces the origins of the SUV to U.S. automakers' efforts to circumvent CAFE (Corporate Average Fuel Economy), the stringent fuel-economy laws of the 1970s that contributed to Detroit's painful decline during that decade. Since light trucks were exempt from the tough new standards, U.S. automakers exploited the loophole and put passenger-car bodies on truck frames. Thus was born the SUV.

The new vehicles caught on big. But there was a downside to the love affair: Because SUVs were taller and narrower than passenger cars, they had an alarming tendency to roll over -- sometimes at speeds as low as 20 miles per hour. And Detroit knew it. FRONTLINE focuses on Ford, the leading seller of SUVs, and uses internal corporate documents, federal regulatory deliberations, and filings from lawsuits to tell the story.

"Rollover" includes footage of a lawsuit deposition in which a Ford engineer reveals that his company knew its first big-selling SUV, the Bronco II, was killing people in rollovers much more often than other SUVs. What's more, the rollover problem had actually been discovered in early road tests conducted prior to the Bronco II's release. To address the problem, Ford engineers recommended lowering the vehicle's center of gravity and widening its track by two inches to increase its stability. Doing so, however, would have delayed production and pushed back the vehicle's release date -- a decision that would have been extremely costly. Ford executives opted not to make the design change.

"There was nobody working at Ford Motor Company that had the courage to knock on the chairman and chief executive's door and say ... 'By the way, we need another 18 months,'" says Tab Turner, an attorney who has handled hundreds of SUV rollover lawsuits. "Nobody was going to do that."

The same dilemma would confront Ford Motor Company several years later, when a highly negative Consumer Reports review of the Bronco II threatened to sabotage the debut of what would eventually become the world's best-selling SUV: the Ford Explorer. When the Explorer's prototype exhibited the same rollover problem in test runs as the Bronco II, engineers once again proposed lowering the vehicle's center of gravity and widening its track. Again, company executives opted for less costly modifications. [See a video excerpt from the program dealing with this episode.]

"They came to a fork in the road," Turner says. "'Do we fix this vehicle ... and take the time to do it right and save lives? Or do we go in this direction and cosmetically fix the vehicle?' They chose to cosmetically fix the vehicle."

Ford marketing consultant Martin Goldfarb tells FRONTLINE that such criticism of Ford executives is unfair. "The reality is that there are choices to make," Goldfarb says. "[Ford] wanted to produce a product that would sell to this segment of the market at this price point. You couldn't put everything in it that you want. Something had to come out. And management has to make those choices. But to assume that management is morally irresponsible because they don't put everything they know about safety in every vehicle is, I think, being unfair."

FRONTLINE sought interviews with Ford's then-president Don Petersen and Explorer project manager Roger Simpson, both of whom declined. But in a court deposition, Simpson testified that the company was concerned about the cost of making engineering changes that "did not offer that much improvement to the vehicle."

This report also examines why the SUV rollover problem and rising death toll weren't investigated more forcefully by the National Highway Traffic Safety Administration (NHTSA), the federal agency charged with overseeing auto-safety standards. FRONTLINE interviewed a number of former NHTSA engineers, officials, and observers who claim that the agency's public-safety mandate was compromised by the Reagan and first Bush administrations' commitment to deregulation and desire to boost the American auto industry. A case in point: NHTSA's refusal in 1990 to order a recall of the Bronco II.

"The Bronco II was the big investigation," says Joan Claybrook, NHTSA director under President Carter and a critic of the agency's later handling of the SUV issue during the 1980s and 1990s. "It was the bad actor, and when [NHTSA] refused to do a recall of that vehicle it gave a pass to every other SUV. It essentially sent a message to Detroit: 'You can make your SUV as rollover-prone as you want to, this agency is not going to find that's a defect.'"

But Maj. Gen. Jerry Curry, NHTSA director from 1989 to 1992 under George H.W. Bush, counters that it is all a matter of consumer choice. "I like to go off-road where I live. And I think people like me want that kind of vehicle. Should I have the right to buy that vehicle? Absolutely. Should the manufacturers then make than kind of vehicle? Yes. Is it more dangerous than a vehicle that is lower and wider? Yes. I'll take the tradeoff."

"Rollover" concludes on this ironic note: Outside the Texas State Capitol, as FRONTLINE interviews the organizer of a group of parent activists whose children were killed in SUV rollovers, a loud crash is heard. As the cameras roll, rescue workers attempt to free a female driver from her overturned SUV. It was not a Ford Explorer. The tires were intact.